Palace officials said the prince, who will turn 91 on Saturday, was taken to the King Edward VII Hospital in London from Windsor Castle on Monday as a precaution and will remain under observation for a few days, according to The Associated Press.
The palace said Prince Philip was "understandably, disappointed about missing this evening's Diamond Jubilee Concert," according to The Associated Press.
At the event, Prince Charles noted his father's absence as he addressed the crowd.
"Only sad thing is that my father couldn't be here with us," Charles said. "If we shout loud enough, he might just hear us in hospital."
Philip, the duke of Edinburgh, married Princess Elizabeth in 1947. She took the throne as queen six years later.
The Diamond Jubilee went on as planned as many members of the royal family, including Charles, his wife Camilla, Duchess of Cornwall, and Princes William and Harry sat in a royal box to watch the show.